U.S. patent number 8,417,154 [Application Number 12/559,078] was granted by the patent office on 2013-04-09 for image forming apparatus with connecting portion for shaft misalignment.
This patent grant is currently assigned to Fuji Xerox Co., Ltd.. The grantee listed for this patent is Hiroaki Nieda. Invention is credited to Hiroaki Nieda.
United States Patent |
8,417,154 |
Nieda |
April 9, 2013 |
Image forming apparatus with connecting portion for shaft
misalignment
Abstract
An image forming apparatus is provided and includes: a rotating
member; an engaging member to be removably engaged with the
rotating member; a driving force transmitting member to be rotated
and driven by a driving source; and a connecting portion that
connects the engaging member to the driving force transmitting
member so that the engaging member and the driving force
transmitting member are movable in a misaligned direction and an
axial direction. The connecting portion includes a connecting
member, a pair of spherical members provided on respective ends of
the connecting member, at least one of which is movable in the
axial direction with respect to the engaging member and the driving
force transmitting member, and a pair of fixing members that fix
the pair of spherical members to the engaging member and the
driving force transmitting member.
Inventors: |
Nieda; Hiroaki (Saitama,
JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Nieda; Hiroaki |
Saitama |
N/A |
JP |
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Assignee: |
Fuji Xerox Co., Ltd. (Tokyo,
JP)
|
Family
ID: |
42560017 |
Appl.
No.: |
12/559,078 |
Filed: |
September 14, 2009 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20100209144 A1 |
Aug 19, 2010 |
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Foreign Application Priority Data
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Feb 17, 2009 [JP] |
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2009-033480 |
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Current U.S.
Class: |
399/167 |
Current CPC
Class: |
G03G
21/1647 (20130101); G03G 15/757 (20130101); G03G
2221/1657 (20130101) |
Current International
Class: |
G03G
15/00 (20060101) |
Field of
Search: |
;399/167,116 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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60-249729 |
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Dec 1985 |
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JP |
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2002-048148 |
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Feb 2002 |
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JP |
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2002328528 |
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Nov 2002 |
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JP |
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2006-072160 |
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Mar 2006 |
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JP |
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2006-139230 |
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Jun 2006 |
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JP |
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2006-163232 |
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Jun 2006 |
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JP |
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2007-51692 |
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Mar 2007 |
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JP |
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2007-069868 |
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Mar 2007 |
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JP |
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2007-121774 |
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May 2007 |
|
JP |
|
2007-240007 |
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Sep 2007 |
|
JP |
|
Primary Examiner: Gray; David
Assistant Examiner: Roth; Laura
Attorney, Agent or Firm: Morgan, Lewis & Bockius LLP
Claims
What is claimed is:
1. An image forming apparatus comprising: a rotating member; an
engaging member to be removably engaged with the rotating member; a
driving force transmitting member to be rotated and driven by a
driving source; and a connecting portion that connects the engaging
member to the driving force transmitting member so that the
engaging member and the driving force transmitting member are
movable in an misaligned direction and an axial direction, the
connecting portion including a connecting member, a pair of
spherical members provided on respective ends of the connecting
member, at least one of which is movable in the axial direction
with respect to the engaging member and the driving force
transmitting member, and a pair of fixing members that fix the pair
of spherical members to the engaging member and the driving force
transmitting member, further comprising an elastic member disposed
between the engaging member and the driving force transmitting
member and serving to bias the engaging member away from the
driving force transmitting member.
2. The image forming apparatus according to claim 1, wherein the
connecting member is a pole-shaped member, the fixing members are
protruding members provided at respective ends of the pole-shaped
member and protruding in a radial direction from the pole-shaped
member, and each of the spherical members has a smaller outside
diameter than a length of one of the protruding members, and the
protruding members protrude from respective surfaces of the
spherical members attached to the respective ends of the
pole-shaped member.
3. The image forming apparatus according to claim 2, wherein the
spherical member is made of a resin, has a hole which the
pole-shaped member is fitted into and a groove which the fixing
member is fitted into, and is assembled by fitting the spherical
member around an end of the pole-shaped member and the fixing
member.
4. An image forming apparatus comprising: a plurality of
photosensitive members; a plurality of engaging members to be
removably engaged with the photosensitive members; a plurality of
driving force transmitting members to be rotated and driven by a
driving source; and a plurality of connecting portions that connect
the engaging members to the driving force transmitting members so
that the engaging members and the driving force transmitting
members are movable in a misaligned direction and an axial
direction, each of the connecting portions including a connecting
member, a pair of spherical members provided on respective ends of
each of the connecting members, at least one of which is movable in
the axial direction with respect to the engaging members and the
driving force transmitting members, and a pair of fixing members
that fix the pair of spherical members to the engaging members and
the driving force transmitting members, further comprising an
elastic member disposed between the engaging members and the
driving force transmitting members and serving to bias the engaging
members away from the driving force transmitting members.
Description
CROSS-REFERENCE TO RELATED APPLICATION
This application is based on and claims priority under 35 USC
.sctn.119 from Japanese Patent Application No. 2009-033480 filed
Feb. 17, 2009.
BACKGROUND
(i) Technical Field
The present invention relates to an image forming apparatus.
(ii) Related Art
There has been known an image forming apparatus including a drive
transmitting device for transmitting a driving force applied from a
driving motor to a photosensitive member serving as a rotating
member by using a gear or a belt.
SUMMARY
According to an aspect of the invention, there is provided an image
forming apparatus including:
a rotating member;
an engaging member to be removably engaged with the rotating
member;
a driving force transmitting member to be rotated and driven by a
driving source; and
a connecting portion that connects the engaging member to the
driving force transmitting member so that the engaging member and
the driving force transmitting member are movable in a misaligned
direction and an axial direction,
the connecting portion including a connecting member, a pair of
spherical members provided on respective ends of the connecting
member, at least one of which is movable in the axial direction
with respect to the engaging member and the driving force
transmitting member, and a pair of fixing members that fix the pair
of spherical members to the engaging member and the driving force
transmitting member.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the present invention will be described in detail
based on the following figures, wherein:
FIG. 1 is a view showing a schematic structure of an image forming
apparatus according to an exemplary embodiment of the
invention;
FIG. 2 is a perspective view showing a main part of an image
forming unit;
FIG. 3 is a perspective view showing an appearance of a
photosensitive member rotation driving device;
FIG. 4 is a front view showing a coupling member of the
photosensitive member rotation driving device;
FIG. 5 is a front view showing an inside of a coupling side case as
seen from the rear;
FIG. 6 is a sectional view taken along the A-A line in FIG. 3;
FIG. 7 is an exploded perspective view showing a connecting
portion;
FIG. 8 is a front view showing a fourth gear;
FIG. 9 is a front view showing the coupling member illustrated in
FIG. 3 as seen from the case side;
FIG. 10 is a sectional view taken along the B - B line in FIG. 3,
illustrating a state in which a shaft misalignment between the
fourth gear and a coupling portion has not occurred;
FIG. 11 is a sectional view taken along the B - B line in FIG. 3,
illustrating a state in which a shaft misalignment between the
fourth gear and the coupling portion has occurred; and
FIG. 12 is a chart showing measurements of register misalignment of
the embodiment and a comparative example.
DETAILED DESCRIPTION
FIG. 1 is a view showing a schematic structure of an image forming
apparatus according to an exemplary embodiment of the invention. An
image forming apparatus 10 is a digital color printer, for example,
and has such a structure as to carry out an image processing of
image data transmitted from an upper device, for example a personal
computer, with an image processing portion (not shown), converting
the data into image data of respective colors of yellow (Y),
magenta (M), cyan (C) and black (K), and to then form a color image
on a paper based on the image data of the respective colors. The
image forming apparatus 10 may be a copying machine, a facsimile
machine, or a composite machine having the functions of a copying
machine, a printer, a scanner and a facsimile machine.
The image forming apparatus 10 includes a housing 11 which is
almost box-shaped, and a paper supplying tray 12 for accommodating
a paper P to be a recording medium is removably provided on a lower
part in the housing 11, a paper discharging portion 13 for
discharging the paper P subjected to recording is provided on an
upper part of the housing 11, and a paper feeding path 14 extending
from the paper supplying tray 12 to the paper discharging portion
13 is formed. The paper feeding path 14 is provided with a pickup
roll 14a for taking the paper P one sheet at a time from the paper
supplying tray 12 into the paper feeding path 14, a correcting roll
14b for correcting a skew of the paper P, and a feeding roll 14c
for feeding the paper P.
Moreover, the image forming apparatus 10 has an image forming
portion 20 on a central part in the housing 11. The image forming
apparatus 20 includes an intermediate transferring belt 33
stretched over a driving roll 30, a backup roll 31 and a driven
roll 32 and circulated and moved in the direction of the arrow in
the drawing, image forming units 21Y, 21M, 21C and 21K disposed
removably at a certain interval from each other on the outside of
the intermediate transferring belt 33 and having a photosensitive
member 22 serving as a rotating member on which toner images for
respective colors of Y, M, C and K are formed while rotating in the
direction of the arrow in the drawing, and primary transferring
rolls 26Y, 26M, 26C and 26K which are disposed inside of the
intermediate transferring belt 33 and which cause a toner image
formed on a surface of the photosensitive member 22 to be
transferred to the intermediate transferring belt 33.
The image forming units 21Y, 21M, 21C and 21K have the same
structures. Each of the image forming units 21Y, 21M, 21C and 21K
includes the photosensitive member 22, a charging device 23 for
uniformly charging the surface of the photosensitive member 22, a
developing device 24 for developing, with a toner, an electrostatic
latent image formed on the surface of the photosensitive member 22
by an exposing device 27 and thus form a toner image on the surface
of the photosensitive member 22, and a photosensitive member
cleaning portion 25 for collecting the toner remaining on the
surface of the photosensitive member 22.
The developing device 24 has a housing 24a for accomodating the
toner, and the housing 24a includes a developing roll 24b for
supplying a toner to the photosensitive member 22 and developing,
with the toner, the electrostatic latent image formed on the
photosensitive member 22, a supplying auger 24c for supplying the
toner to the developing roll 24b, and a stirring auger 24d for
stirring the toner and supplying the toner to the supplying auger
24c. Toners having the respective colors are supplied from toner
boxes 35Y, 35M, 35C and 35K to the developing device 24.
The exposing device 27 includes four semiconductor lasers (not
shown) for emitting laser beams modulated according to image data
of the respective colors of Y, M, C and K, a polygon mirror 27a for
branching the laser beam emitted from each of the semiconductor
lasers, and a plurality of mirrors 27b for reflecting the laser
beam branched by the polygon mirror 27a to irradiate the
photosensitive member 22, thereby forming an electrostatic latent
image on the surface of the photosensitive member 22. The exposing
device 27 is sealed by a frame 27c so as not to be contaminated
with the toner. An upper part of the frame 27c is transparent
glass.
The image forming portion 20 is provided with a secondary
transferring roll 34 facing the backup roll 31 with the
intermediate transferring belt 33 interposed therebetween, and a
toner image on the intermediate transferring belt 33 is secondarily
transferred to the paper P in a nip region formed by the secondary
transferring roll 34 and the backup roll 31.
In the image forming portion 20, moreover, a belt cleaning portion
40 is provided facing the driving roll 30 with the intermediate
transferring belt 33 interposed therebetween, upstream of the image
forming unit 21Y. The belt cleaning portion 40 is pressed toward
the driving roll 30 side, and scrapes away and collects the toner
remaining on the intermediate transferring belt 33.
FIG. 2 is a perspective view showing a main part of the image
forming unit. Since the image forming units 21Y, 21M, 21C and 21K
have the same structures, the image forming unit 21Y will be
described as an exemplary embodiment. The image forming unit 21Y
has a coupling member 210 connected to a coupling member of a
photosensitive member rotation driving device which will be
described below, a cover 211 for protecting the photosensitive
member 22, and a hole opening portion 212 to which the toner is
supplied from the toner box 35Y. The cover 211 is constituted to be
slid and removed from the image forming unit 21Y when attaching the
image forming unit 21Y to the housing 11. The coupling member 210
has a shaft 210a which is attached to a rotating shaft of the
photosensitive member 22 and is coaxial with the rotating center of
the photosensitive member 22, and a pair of locking portions 210b
disposed around the shaft 210a.
FIG. 3 is a perspective view showing the appearance of the
photosensitive member rotation driving device. A photosensitive
member rotation driving device 100 includes a case 101 having a
coupling side case portion 101A and a non-coupling side case
portion 101B. A motor 102 serving as a driving source and four
coupling portions 110 to which the coupling members 210 of the
photosensitive members 22 is connected are provided on the coupling
side of the case 101. The photosensitive member rotation driving
device 100 is attached to the housing 11 at the non-coupling side
of the image forming units 21Y, 21M, 21C and 21K with screws
through attaching holes 101a of the coupling side case 101A. The
coupling portion 110 includes coupling members 111Y, 111M, 111C and
111K and a spring receiving member which will be described below.
In the following description, each of the coupling members 111Y,
111M, 111C and 111K will be generally referred to as a coupling
member 111.
FIG. 4 is a front view showing the coupling member 111 of the
photosensitive member rotation driving device 100. The coupling
member 111 includes an elliptical protruded portion 111b having
within it a slot 111a in which the shaft 210a of the coupling
member 210 shown in FIG. 2 is fitted. Moreover, an L shape is
formed by an engaging portion 111c with which the locking portion
210b of the coupling member 210 is engaged and a protruded portion
111d formed extending from the side of the elliptical protruded
portion 111b. The coupling member 111 is rotated in the direction
of the arrow in FIG. 4 so that the locking portion 210b on the
photosensitive member 22 side is engaged with the engaging portion
111c.
FIG. 5 is a front view showing the inside of the coupling side case
101A as seen from the non-coupling side. A gear train 120 to be
rotated and driven by the motor 102 is accommodated in the case 101
as shown in FIG. 5. The gear train 120 is constituted by a pair of
left and right first gears 121 engaged with an output gear 102a
provided on the output shaft of the motor 102, a pair of left and
right second gears 122 engaged with the pair of left and right
first gears 121 respectively, a pair of left and right third gears
123 engaged with the pair of second gears 122, a pair of left and
right fourth gears 124 serving as driving force transmitting
members and engaged with one of the third gears 123, and a pair of
left and right fourth gears 124 to be engaged with the other third
gear 123. The fourth gear 124 is coupled to the coupling portion
110 shown in FIG. 3 through a coupling portion which will be
described below.
FIG. 6 is a sectional view taken along the A lines in FIG. 3. The
coupling portion 110 and the fourth gear 124 are connected to each
other through a connecting portion 130 movably in misaligned and
axial directions. A coil spring 103 and a washer 104 are disposed
between the coupling portion 110 and the fourth gear 124.
The connecting portion 130 includes a shaft 131 serving as a
connecting member or a pole-shaped member, a pair of spherical
members 132 which are provided on both ends of the shaft 131 and
are movable in an axial direction with respect to the coupling
member 111 and the fourth gear 124, and a pair of pins 133 serving
as fixing members or protruded members which fix the pair of
spherical members 132 with respect to a rotating direction of the
coupling member 111 and the fourth gear 124. Even if rotating shaft
axes of the coupling member 111 and the fourth gear 124 which will
be described below are misaligned, if the coupling member 111 and
the fourth gear 124 contact each other through spherical members
132, the shapes of the other portions may be selected as
appropriate and there will be no problem.
The fourth gear 124 has formed around its central axis teeth 124a
formed on the gear circumferential surface, and a shaft portion
124b supported rotatably at side toward the coupling side case
101A, a shaft portion 124c supported rotatably on the side toward
non-coupling side case portion 101B, and a spherical member housing
portion 124d for accommodating the spherical member 132 so that it
can move in the axial direction which are formed on a rotating
central axis. A hole 124e is formed in the spherical member housing
portion 124d. The hole 124e has a slightly greater inside diameter
than the outside diameter of the spherical member 132.
In the fourth gear 124, the shaft portion 124b is rotatably
supported at the coupling side case 101A by a supporting member
105A and the shaft portion 124c is rotatably supported at the
non-coupling side case 101B by a supporting member 105B. The
supporting member 105A is attached to the coupling side case 101A
with a screw 106, and the supporting member 105B is attached to the
non-coupling side case 101B with a screw 106.
The coupling portion 110 comprises the coupling member 111 and a
spring receiver 112 which is an elastic member fixed to the
coupling member 111 and which receives the coil spring 103. The
coil spring 103 biases the coupling portion 110 away from the case
101.
The coupling member 111 includes a spherical member housing portion
111e along whose axis the spherical member 132 is inserted and
accommodated movably. A hole 111f is formed in the spherical member
housing portion 111e. The hole 111f has a slightly greater inside
diameter than the outside diameter of the spherical member 132.
FIG. 7 is an exploded perspective view showing the connecting
portion 130. The spherical member 132 has a part 132a whose surface
is part of a sphere, and there are formed a hole 132b in which the
shaft 131 is fitted and a groove 132c in which the pin 133 is
fitted. The shaft 131 is cylindrical and has through holes 131a
formed on both ends. The connecting portion 130 is assembled by
fitting the pins 133 in the through holes 131a on both ends of the
shaft 131 and fitting the spherical member 132 around an end of the
shaft 131 and the pin 133. The spherical member 132 has a smaller
outside diameter than the length in the axial direction of the pin
133, and is formed from a resin in order to easily carry out
fitting around the end of the axis 131 and the pin 133. Although
the shaft 131, the pin 133 and the spherical member 132 are
constituted by three different members in the embodiment, two of
the three members or all three members may be formed integrally
into a single member.
FIG. 8 is a front view of the fourth gear 124. The fourth gear 124
has a pair of grooves 124f formed on the spherical member housing
portion 124d. The pin 133 of the connecting portion 130 is fitted
in the groove 124f. The pin 133 of the connecting portion 130 is
fitted in the groove 124f of the fourth gear 124 so that a rotating
force of the fourth gear 124 is transmitted to the shaft 131
through the pin 133.
FIG. 9 is a front view showing the coupling member 111 illustrated
in FIG. 3 as seen from the case 101 side. In the coupling member
111, a groove 111g for fitting the pin 133 of the connecting
portion 130 is formed on the spherical member housing portion 111e.
The pin 133 of the connecting portion 130 is fitted in the groove
111g of the coupling member 111 so that a rotating force of the
shaft 131 is transmitted to the coupling member 111 through the pin
133.
(Operation of Photosensitive Member Rotation Driving Device)
FIG. 10 is a sectional view taken along a B-B line in FIG. 3,
illustrating a state in which a shaft misalignment is not caused
between the fourth gear 124 and the coupling portion 110, and FIG.
11 is a sectional view taken along the B-B line in FIG. 3,
illustrating a state in which the shaft misalignment is caused
between the fourth gear 124 and the coupling portion 110. An
operation of the photosensitive member rotation driving device 100
will be described below with reference to FIGS. 10 and 11.
When the motor 102 of the photosensitive member rotation driving
device 100 is driven by a control of a controlling portion which is
not shown, a rotating force of the motor 102 is transmitted from
the output gear 102a provided on the output shaft of the motor 102
to the first gear 121 of the gear train 120, and then is
transmitted to the four fourth gears 124 through the second gears
122 and the third gears 123. The rotating force transmitted to the
fourth gear 124 is transmitted to the coupling portion 110 through
the connecting portion 130. The image forming units 21Y, 21M, 21C
and 21K connected to the coupling portion 110 are rotated at the
same time in the same direction.
The toner images formed on the photosensitive members 22 of the
image forming units 21Y, 21M, 21C and 21K are transferred onto the
intermediate transferring belt 33, and furthermore, are transferred
onto the paper P so that a color image having little register
misalignment is formed.
As shown in FIG. 10, in the state in which the shaft misalignment
is not caused between the fourth gear 124 and the coupling portion
110, rotating axes La, Lb and Lc of the fourth gear 124, the shaft
131 of the connecting portion 130, and the coupling portion 110,
respectively, are coaxial. In this case, the angular speed of the
fourth gear 124 is maintained to be constant as it is transmitted
to the shaft 131 of the connecting portion 130 and the coupling
portion 110.
As shown in FIG. 11, in the state in which shaft misalignment is
caused between the fourth gear 124 and the coupling portion 110,
the rotating axis La of the fourth gear 124 is misaligned with the
rotating axis Lc of the coupling portion 110 by a shift amount e.
The rotating axis Lb of the shaft 131 of the connecting portion 130
is tilted with respect to the other rotating axes La and Lc. In
this case, the angular speed of the fourth gear 124 changes by an
amount corresponding to the tilt angle of the shaft 131 at the
fourth gear 124 side of the connecting portion 130. However, this
change is canceled out by the change in angular speed which occurs
at the coupling portion 110 side connecting portion 130, so that
the coupling portion 110 has the same angular speed as the fourth
gear 124.
FIG. 12 shows measurements of the register misalignment in the
embodiment and in a comparative example. In the configuration of
the comparative example, the spherical member was omitted and the
ends of the shaft 131 were connected to the coupling member and the
fourth gear through a single pivot shaft each. The register
misalignment indicates the color shift of the toner image for each
of Y, M, C and K. From FIG. 12, it is apparent that the register
misalignment is increased with an increase in the shaft
misalignment in the comparative example, and that the register
misalignment hardly changes at all even if the shaft misalignment
is increased in the embodiment.
The invention is not restricted to the embodiment, and various
changes can be made without departing from the scope of the
invention. For example, although the photosensitive member has been
described as the rotating member in the embodiment, the rotating
member of the invention may be a developing roll in a developing
device, a feeding roll for delivering a paper, a roll for moving an
intermediate transferring belt or other rotating members
Although both of the spherical members 132 can be moved in the
axial direction with respect to the coupling member 111 and the
fourth gear 124 in the embodiment, it is also possible to employ a
structure in which they can be moved in the axial direction with
respect to one of these.
* * * * *